SERUM DIAGNOSIS OF PAROXYSMAL HEMOGLOBINURIA 379 



the serum with nine parts of normal salt solution, and to a series of test- 

 tubes add increasing amounts of 0.05 c.c., 0.1 c.c., 0.2 c.c., 0.4 c.c., 0.8 

 c.c., 1 c.c., and 2 c.c., corresponding respectively to 0.005, 0.01, 0.02, 

 0.04, 0.08, 0.1, and 0.2 c.c. of the undiluted serum. Add 1 c.c. of a 5 

 per cent, dilution of fresh amboceptor-free guinea-pig serum as com- 

 plement, and 1 c.c. of a 2.5 per cent, suspension of the corpuscles; 

 sufficient salt solution is added to make the total volume about 4 c.c. 

 After shaking, the tubes are placed in the incubator at 37 C. for two 

 hours, removed, and the results read, or the tubes may be placed in a 

 refrigerator overnight and the results read in the morning. 



SERUM DIAGNOSIS OF PAROXYSMAL HEMOGLOBINURIA 



A hemolytic substance may be demonstrated in the blood-serum of 

 most cases of paroxysmal hemoglobinuria at certain periods. Although 

 the exact nature of this substance is unknown, it has many of the prop- 

 erties of isohemolysins, being capable of sensitizing the red corpuscles 

 of the patient or those of a normal person at a low temperature, hemoly- 

 sis being effected in the presence of fresh serum, presumably with com- 

 plement, and best at body temperature. 



According to Cook, about 90 per cent, of hemoglobinurics show a 

 positive Wassermann reaction. Landsteiner found that about 10 

 per cent, of paretics showed similar reactions, and other observers have 

 reported finding isohemolysins in epileptics and idiots. Malaria and 

 trypanosomiasis have also been regarded as causes of this condition, the 

 most evidence, however, indicating that the etiology has a luetic origin. 

 It is possible that the hemotoxin is similar to the hemolysin of cobra 

 venom, being in the nature of an amboceptor complemented by the 

 fatty acids or lecithin of red corpuscles (endocomplement) or by a serum 

 complement. 



First Method. According to Ehrlich, a small tourniquet should be 

 applied about the base of one of the patient's fingers, and this is then 

 kept immersed in ice-cold water for half an hour. Blood from the finger 

 thus constricted is then collected in a Wright capsule, and blood from a 

 finger of the other hand is used as a control. Both are allowed to clot 

 and are then centrifugalized. The serum from the finger held in iced 

 water is tinged red from dissolved hemoglobin, whereas the control 

 serum is not tinged or at least not tinged so deeply. 



Second Method. Donath and Landsteiner have applied Ehrlich's 

 method in vitro. Their method consists of collecting blood in a small 



